My MacBook Pro was (temporarily) frozen with a warning saying 'browser phishing ahead', and giving me a phone number to phone "immediately" + go to a website called mac-virusy. . I didn't do as asked (too suspicious). Shutting down and reopening didn't remove the freeze (this was on Safari), but I could use Firefox without problems. After 20 minutes of panic (aaaaargh - virus!!!) I tried again, and all was back to normal. Does anyone have any idea what happened? Thanks in advance.